Caseless ammunition with the primer operatively supported to the aft end of the projectile



April 22, 1969 P. J. HENSLEY 3, 3

CASELESS AMMUNITION WITH THE PRIMER OPERATIVELY SUPPORTED TO THE AFT ENDOF THE PROJECTILE Flled Lee. 28, 1967 Sheet of 2 2e 32 2s l0 I2 l l r 20l6 1e 22 n wk L3: l\\ W 4 FIG. I

FIG. 2

PERRY J. HENSLEY INVENTOR.

BY w ggw ATTORNEY Apnl 22, 1969 P. J. HENSLEY 3,439,635

CASELESS AMMUNITION WITH THE PRIMER OPERATIVELY SUPPORTED TO THE AFT ENDOF THE PROJECTILE Filed Dec. 28, 1967 FIG. 4

PERRY J. HENSLEY INVENTOR.

ATTORNEY Sheet of2.

United States Patent 3,439,635 CASELESS AMMUNITION WITH THE PRIMEROPERATIVELY SUPPORTED TO THE AFT END OF THE PROJECTILE Perry J. Hensley,Magna, Utah, assignor to Hercules Incorporated, Wilmington, Del., acorporation of Delaware Filed Dec. 28, 1967, Ser. No. 694,205 Int. Cl.F42b 9/00 US. Cl. l0238 8 Claims ABSTRACT OF THE DISCLOSURE A round ofcaseless ammunition is provided with the primer operatively supported tothe aft end of the projectile. Both conventional and combustible primerscan be employed.

This invention relates to a novel method for priming a round of caselessammunition. More particularly, this invention relates to a round ofcaseless ammunition wherein the projectile provides the supportnecessary for operation of the primer.

One of the major problems in the state of the development of caselessammunition has been the poor reliability of the round. Heretofore,combustible primers have been used exclusively with caseless ammunitionsince it is required that the chamber of the firearm in which theserounds are fired be clean after each firing. The poor reliability of thecaseless round is attributed to the combustible primer, and inparticular to the lack of a rigid anvil in the combustible primer. Thefunction of an anvil in a primer is to provide support for the primingmixture so that it is crushed by the action of a firing pin. Propellantformulations which are suitable for use as a propellant charge incaseless ammunition do not have the rigidity necessary to provide thesupport for reliable ignition of combustible primers. Attempts toincrease the reliability of combustible primers have included theaddition of highly sensitive explosive materials to the priming mixture.

Conventional type primers have not been used with caseless ammunition,since there is no method to remove the noncombustible parts of theconventional primer from the chamber of the firearm. Conventionalprimers used with cartridge type ammunition are secured to the base ofthe cartridge case and are removed from the chamber of the firearm whenthe spent cartridge case is ejected. The metal cartridge case ofcartridge type ammunition provides the support needed for operation ofthe primer.

It is an object of this invention to provide a highly reliable primingsystem for caseless ammunition.

It is another object of this invention to provide a simple, economical,and safe method of priming caseless ammunition.

It is another object of this invention to provide a round of caselessammunition wherein the projectile, provides the support necessary forreliable operation of the primer.

It is still another object of this invention to provide a round ofcaseless ammunition wherein the primer can be of the combustible orconventional type.

Other objects of this invention will, in part, be obvious and will, inpart, appear hereinafter. For a complete understanding of the nature andthe objects of this inven- Patented Apr. 22, 1969 ice tion, reference ismade to the following detailed description and drawings.

In accordance with this invention, there is provided a round of caselessammunition having in combination, a propellant charge with an axial borethroughout, a projectile, and a primer in axial alignment with theprojectile and operatively supported to the aft end of the projectile.

The projectile with the primer supported to its aft end is positionedand secured within the axial bore of the propellant charge. The diameterof the axial bore is substantially equal to or greater than the maximumoutside diameter of the projectile so that the projectile can be housedwithin the bore of the propellant charge. The wall of propellant formedby the axial bore in the propellant charge can surround the primer andthe projectile. A round of caseless ammunition in which the projectileis housed in propellant as described is referred to hereinafter as atelescoped round of caseless ammunition. The telescoped rounds of thisinvention include rounds in which the primer and the entire length ofprojectile are surrounded by propellant and those in which the primerand a part of the length of the projectile are surrounded -bypropellant.

Telescoped rounds of caseless ammunition having the primer supported tothe aft end of the projectile are illustrated in the accompanyingdrawings.

FIG. 1 represents a vertical section of a longitudinal view of atelescoped round in the loaded and firing positions wherein acombustible primer is supported within an axial recess at the aft end ofthe projectile.

FIG. 2 illustrates a vertical section of a longitudinal view of atelescoped round of caseless ammunition with a conventional metal primersupported within an axial recess at the aft end of the projectile.

FIG. 3 illustrates a vertical section of a longitudinal view of anembodiment of a telescoped round with a combustible primer supported tothe base of the projectile.

FIG. 4 illustrates a vertical section of a longitudinal view of anembodiment of a telescoped round with a conventional metal primersupported to the aft end of the projectile.

In FIG. 1 a telescoped round is shown having a propellant charge 10 withan axial bore 12 throughout, and a projectile 14 secured within theaxial bore 12. The projectile 14 has an axial recess 16 in the aft end.The axial recess 16 in the aft end of projectile 14 is filled withconventional priming mixture 18. The priming mixture 18 is sealed intoaxial recess 16 with a disc of moistureproof combustible material 20.The base 22 of the axial recess provides the support necessary forreliable ignition of the priming mixture 18.

When a telescoped round is to be fired the projectile 14 is chambered atposition 24 by the forward movement of a reciprocating bolt 26. Theprojectile 14 is moved forward in relation to the propellant charge 10to the chambered position 24. In this position forward obturation issubstantially accomplished.

The reciprocating bolt 26 has a bolt extension 28 with a reduceddiameter which enters into the axial bore 12 of the propellant charge,contacts the rim 30 forming the extreme aft end of the projectile, andchambers the projectile 14. The bolt travel is predetermined by weapondesign to effectively chamber the projectile 14. The telescoped round isfired when a firing pin 32 is driven forward into the primer mixture 18.The crushing action 3 provided by the firing pin 32 being driven intothe primer mixture 18 supported by the projectile 14, initiates thepriming mixture 18. The blast from the primer is reflected off the boltextension 28 and ignites the propellant charge 10.

In FIG. 2 a conventional metal primer comprised of a cup 34, an anvil 36having circular cuts along its edges to provide a passage way forflames, a waterproof combustible seal 38, and a priming mixture 40 isinstalled in an axial recess 42 in the base of the projectile 44. Theprojectile 44 has radial vents 46 drilled from the outside of theprojectile to center of the bottom of axial recess 42. The radial vents46 provide the paths for the flames from the detonated primer mixture 40to reach the propellant charge 48. The primer cup 34 and anvil 36, leavethe chamber of the firearm with the projectile 44.

FIG. 3 illustrates an embodiment of a telescoped round with acombustible primer supported at the base of the projectile and in axialalignment therewith. In FIG. 3 a combustible primer cup 50 is adhesivelysecured to the base of projectile 52. The primer cup is filled with aconventional priming mixture 54 which is held in place with acombustible seal 56. The primer is initiated by crushing of the primingmixture 54 provided by the action of a firing pin (not shown) impingingon the priming mixture 54 which is supported by the base of theprojectile 52.

FIG. 4 illustrates an embodiment of a telescoped round with aconventional metal primer supported to the aft end of the projectile andin axial alignment therewith. In FIG. 4 support members 60 are securedat one end to the base of the projectile 62 and at the opposite end tothe conventional primer 58. The space between the base of the projectile62 and the primer 58 provides a path whereby the primer flames canreflect oil? the base of the projectile to ignite the propellant charge64. The projectile provides the support necessary for operation of theprimer 58. The primer 58 leaves the barrel of the firearm attached tothe projectile 62.

In accordance with this invention the projectile must be chambered priorto initiation of the primer to provide the support necessary forreliable operation of the primer. Therefore, the aft end of theprojectile must provide a surface, spaced from the primer, for receivingthe chambering means so that the primer is not initiated duringchambering of the projectile. This surface can be a peripheral area oran extension member at the base of the projectile spaced from theprimer.

The propellant charge can have any outside configuration desired. Thepropellant charge can be prepared from a single base, double base,triple base, or composite propellant granules. The propellant charge canbe made by a molding technique wherein small granules of propellant arebonded together by a suitable binder. In this method a mold is filledwith granules of propellant, a binder is added, and the mold ispressurized at from about 500 p.s.i. to about 2000 p.s.i. for fromfractions of a second to about a minute. The propellant charge is thenremoved from the mold and dried. A suitable binder for single base,double base and triple base propellant is a mixture of collodian andacetone. A binder suitable for composite type propellant is dependent onthe type of composite but in general it is of the same composition asthe binder of the composite.

The primers which can be employed in this invention include bothcombustible and conventional types.

The combustible type primer in its simplest form can :onsist simply of astandard priming mixture pressed into he aft end of a projectile andsealed with a Waterproof :ombustible seal such as adhesive backedfoiling paper. Combustible primers can also be preprepared. The primerJody can be made from propellant or other combustible material. Theprimer body is tightly packed with priming nixture and sealed with awaterproof combustible seal. The primer can then be secured to the aftend of the projectile, The base of the preprepared combustible primermust be contiguous with the aft end of the projectile for operativesupport to be provided by the projectile.

All types of conventional primers can be used in this invention. Thenoncombustible portion of the conventional primer leaves the chamber ofthe firearm with the projectile. Operative support for the conventionalprimer is provided by securing the primer to the aft end of theprojectile so that flames from the initiated primer have an open pathwhereby they can contact the propellant charge for its ignition.

The priming mixtures employed with combustible and conventional primerscontain the usual priming mixture ingredients such as potassiumchlorate, antimony sulfide, lead sulphocyanide, trinitrotoluol, or otherstandard primer ingredients. The exact composition and amount of primingmixture will depend on the formulation and size of the propellant chargeto be ignited, and should be chosen to provide sufficient pressure andheat for reliable ignition of the propellant charge.

The projectile is secured inside the bore of the propellant charge withadhesive such as nitrocellulose in methyl ethyl ketone which will form abond between the projectile and the propellant surface. Other adhesiveswhich can be used include polyisocyanate resins, epoxy resins andcellulose acetate lacquers. Other means of securing the projectile inthe bore of the propellant charge include use of a readily combustiblematerial such as Styrofoam in the form of a solid ring or rings. Theserings can be adhesively secured to both the projectile and the bore ofthe propellant charge to secure the projectile therein. Only a smallamount of adhesive is required since the function of the adhesive is toprevent the projectile from loosening during handling operations.

The telescoped rounds of caseless ammunition of this invention can beprepared in any size desired. The amount of propellant in the propellantcharge, the caliber of the projectile, and overall round configurationcan be determined by one skilled in the art depending on such factors asthe firearm for which the round is designed, and the desired range forthe projectile.

What I claim and desire to protect by Letters Patent 15:

1. A telescoped round of caseless ammunition havmg in combination apropellant charge with an axial bore throughout; a projectile; and aprimer in axial alignment with the projectile; said projectile andprimer positioned within the bore of the propellant charge; means foroperatively supporting the primer to the aft end of the projectile;means at the aft end of the projectile, spaced from said primer, forreceiving chambering means for the projectile; and means for securingthe projectile within the bore of the propellant charge.

2. The telescoped round of caseless ammunition of claim 1 wherein theprimer is of the combustible type.

3. The telescoped round of caseless ammunition of claim 1 wherein theprimer is of the conventional type.

4. The telescoped round of caseless ammunition of claim 1 wherein themeans for operatively supporting the primer to the aft end projectilecomprises a projectile with an axial recess in its base, and the primeris of the combustible type secured within said axial recess.

5. The telescoped round of caseless ammunition of claim 4 wherein theprimer is comprised of a priming mixture and a combustible seal, saidpriming mixture held in the axial cavity in the base of the projectileby the combustible seal.

6. The telescoped round of caseless ammunition of claim 1 wherein theprojectile has an axial recess in its base and radial vents passing fromthe base of the axial recess to the outside of the projectile; the meansfor operatively supporting the primer to the aft end of the projectilecomprises the axial recess; and the primer is of the conventional typesecured within said axial recess.

5 6 7. The telescoped round of caseless ammunition of References Citedclaim 1 wherein the means for operatively supporting the UNITED STATESPATENTS primer to the aft end of the projectile comprises the base ofthe projectile and the primer is of the combustible 2 366,412 12/1958Meyer t 1, 102 38 type secured to the base of the projectile. 53,345,945 10/ 1967 Quinlan et a1. 102-38 8. The telescoped round ofcaseless ammuni ion f 3,398,684 8/1968 Kuavle 10299 X claim 1 whereinthe means for operatively supporting the primer to the aft end of theprojectile comprises support ROBERT STAHLPrlmany Exammer' memberssecured at one end to the aft end of the pro- U.S. Cl.X.R. jectile, andsecured at the opposite end to the primer, 10 10240 45 said primer beingof the conventional type.

